Iraninfo-icon and major powers yesterday took stock of their 2015 nuclear deal, with Donald Trumpinfo-icon's imminent inauguration and the death of a moderate former Iranian president raising worries about its future.

Trump, who takes office on January 20, has vowed to dismantle the "disastrous" accord, which saw Iran drastically reduce its atomic activities in exchange for the lifting of painful sanctions.

The death of Akbar Hashemi Rafsanjani on Sunday removed a widely respected backer in Iran of the deal at a time when frustration about the slow pace of sanctions relief is growing.

Yesterday's meeting in Vienna brought together senior diplomats from Iran and the United Statesinfo-icon, Russiainfo-icon, Chinainfo-icon, Britaininfo-icon, Franceinfo-icon and Germanyinfo-icon.

It is the fourth such gathering to review progress implementing the accord since it came into force in January 2016 and was requested by Iran in December after USinfo-icon sanctions legislation was renewed for a decade.

US restrictions under the Iran Sanctions Act targeting mostly Tehraninfo-icon's oilinfo-icon and gas sectors remain suspended but the Islamic Republic still saw the move as a violation of the nuclear deal. There is also disappointment in Iran that many of the economic benefits that President Hassan Rouhani, 68, promised would come from the deal have fallen short.